JCB 1700B Shuttle Shift grinds under heavy load in forward direction.

[garrett41]

Hi guys,

I'm hoping someone where can help me diagnose an issue with my JCB 1700B.

I bought the tractor as a fixer upper a few years ago, and it's not in the best shape, leaks through most of the seals and such, but it runs and drives and digs just fine. It has a 90hp Perkins 4.236 turbo diesel and a 4-speed shuttle shift transmission.

Last year it started being a bit weaker in the forward gears. For example, it used to walk right up hills in 1st or 2nd, and with some throttle it would go up in 3 or 4. However, then it got to a point where it wouldn't go up the hills in any gear but 1, and that took a good bit of throttle.

I changed all the fluids, brakes, oil, transfer case, rear differential and transmission. The trans was a bit low and after those changes, it was working much better. It would go up the hills in 2 again, and 3 under heavy throttle.

Now a few months later, it has started making this unfriendly grinding sound when I'm going up steeper hills or pushing into a big pile of dirt to grab a bucket full. It seems to get worse the heavier I'm into the throttle and it does not happen in reverse at all. The power is still there, but it just makes the grinding noise which sounds like it's coming from right underneath the cab, slightly to the rear of the engine.

At first I thought it was the hydraulic lines cavitating or something due to the numerous low leaks, but it doesn't happen in neutral or reverse while running the hydraulics, and I can dig for hours with the backhoe and it doesn't make the noise.

Any ideas? Is my transmission going out? or maybe just the pump? or torque converter?

Any input would be great. Thanks in advance...

-Garrett

 

[Gale Hawkins]

Garrett I only know one owner for a JCB but it is large perhaps like yours. He bought it when still new like (post lease perhaps) as a fixer upper too. It had a bearing go down in the transmission and it ground up the transmission. He had a shop rebuild it years ago and it is still fine.

That is not a positive story but if you have a failed bearing I will be cheaper to fix it so the transmission does not eat itself IF you even have the same problem.

I would travel in reverse around the place in the mean time.

Our 1983 JD 310B BH will slip in the higher gears going forward but not backwards but I think that is the clutch packs/power shifter or so something. It does not have a torque convert but do not know about a JCB except that are great machines.

 

[garrett41]

Thanks for the input Gale.

I was thinking the same thing. Really hoping I don't have to drop a few grand on a rebuild. However, a newly built one would give me a lot more piece of mind I suppose. Right now as I'm driving it uphill I'm just waiting for it to bust loose and send me rolling back down the hill backwards...

I'll have to see if I can find a local shop around here that has some experience with JCB's. I'm definitely a do-it-yourselfer, but the components on this thing are SOOOO heavy. I'm afraid to tackle it on my own in the garage. Might not be able to lift something back into position, let alone the safety aspect...

Thanks again,
-Garrett

 

[garrett41]

I just wanted to stop back and provide an update. I was out trying to use the backhoe again yesterday and it really started making the grinding noise when I started pushing some dirt around.

I was able to dig the bucket into the ground and leave it in forward, hopped off and got down near the engine bay for a listen. It turns out I was wrong about where the noise was coming from. It sounded like the trans area when in the cab, but it was actually coming from the front of the engine.

I popped the hood up and got back in the cab. I shifted back and forth a few times and then realized what was happening. When I shifted into forward, the torque of the engine was shifting the engine over to the right enough for the fan to start making contact with the lower right portion of the fan shroud. The harder I pushed it, the father it shifted and worse the noise got. When shifting back to neutral it would fall back to center, and in reverse it would edge slightly to the left, but not enough to contact.

I pulled it into the garage and climbed under to take a look. The engine mounts are completely shot. Also, as I jacked up the engine a little, I noticed the mount was rotating on the passenger side of the front of the engine. Upon closer inspection, 1 of 2 bolts was missing from the mount where it connects to the block, so it was sloppy loose.

All that is to say, I need to order a mount-to-block bolt and two new engine mounts and hopefully that'll get me back running smooth. So glad it's not a transmission issue!!!

Do you guys usually run rubber, polyurethane, or solid mounts on your diesel tractors?

Thanks,
-Garrett

 

[Gale Hawkins]

Thanks for the update and glad it was not an internal problem. Those are awesome machines.

 

[garrett41]

Yea, I was really kind of down about it when I thought it was going to be a lot of cash to fix it up.

Tonight I went up and pulled off one of the old engine mounts. It was totally worn out; smashed almost flat.

I was able to fabricate a mount out of some 3/4" thick hard rubber matting I had in the garage. I used a hole saw to cut out a couple of 4" circles. Drilled a hole through the center of each, stacked them, and installed them in the mount position. I wasn't really sure if it was going to work, but I'm really happy with how it turned out.

I pulled the remaining mount-to-block bolt so I can take it to home depot with me tomorrow after work to try to find a replacement. Hope to pull and replace the other mount tomorrow and get everything bolted back up!